WASHINGTON — Attorney General Jeff Sessions has directed federal authorities to review a rash of recent murders involving transgender victims, after such killings have steadily climbed over the past three years.

Speaking Thursday to a national conference on hate crimes, Sessions said that the FBI and the Justice Department’s Civil Rights Division are weighing possible federal intervention in ongoing investigations related to the killings. Reported murders of transgender women have jumped from 16 in 2014 to 27 last year.

“I specifically directed that the files of these cases be reviewed to ensure that there is no single person or group behind these murders or to what extent hate crime motivation lies behind such murders,’’ the attorney general said, adding that he has been receiving “regular updates’’ on the status of the federal effort.

The review appeared to be prompted by a March letter from six Democratic lawmakers, who urged the Justice Department to take notice of the increasing threat. No federal hate crime prosecutions resulted from transgender murders between 2013 and 2015, they said.

Particularly vulnerable, the lawmakers warned, are transgender women who are "four times more likely to be murdered than the general population of all women.'' Already this year, 14 transgender people – mostly women – have been murdered, according to the Human Rights Campaign.

The March 10 letter was signed by Reps. Keith Ellison of Minnesota, Raul Grijalva of Arizona, Mark Pocan of Wisconsin, Barbara Lee of California, Joseph Kennedy of Massachusetts and Jackie Speier of California.

"Over the last few years, transgender Americans and the contributions that they make to our communities have become more visible than ever,'' the letter stated. "However, it is clear that this increased representation has not made our country safer for the transgender community.''

In his Thursday remarks, Sessions expressed his "personal'' interest in the course of the murder investigations, requesting that federal officials "identify ways the department can support the state and local law enforcement... and to determine whether federal action would be appropriate.''

"No person should have to fear being violently attacked because of who they are, what they believe or how they worship,'' the attorney general said.

David Stacy, government affairs director for the Human Rights Campaign, said Sessions' public acknowledgement of the threat to transgender people required additional action.

"Now that Jeff Sessions is finally recognizing the national epidemic of violent hate crimes against transgender people, it is critical that the Department of Justice enhance its efforts to investigate, prosecute and deter these horrible crimes,'' Stacy said.